UIO: add pgprot_noncached() to UIO mmap code

Mapping of physical memory in UIO needs pgprot_noncached() to ensure
that IO memory is not cached. Without pgprot_noncached(), it (accidentally)
works on x86 and arm, but fails on PPC.

Signed-off-by: Jean-Samuel Chenard <jsamch@gmail.com>
Signed-off-by: Hans J Koch <hjk@linutronix.de>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index e8a01f26454..11759080ca5 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -470,6 +470,8 @@ static int uio_mmap_physical(struct vm_area_struct *vma)
 
         vma->vm_flags |= VM_IO | VM_RESERVED;
 
+        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+
         return remap_pfn_range(vma,
                                vma->vm_start,
                                idev->info->mem[mi].addr >> PAGE_SHIFT,